Muffler construction



May 29, 1962 Filed Sept. 18, 195-7 W. H. POWERS MUFFLER CONSTRUCTION 4 Sheets-Sheet 1 INVENTOR. fllfsfl H Ewe/1s,

May 29, 1962 w. H. POWERS MUFFLER CONSTRUCTION '4 Sheets-Sheet 2 Filed Sept. 18, 1957 INVENTOR. 14 [2 6/ b1 70 14 W. H. POWERS MUFFLER CONSTRUCTION May 29, 1962 Filed Sept. 18, 1957' 4 Sheets-Sheet 3 INVENTOR fi dzz er 7 01 76/15,

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y 1962 w. H. POWERS 3,036,654

' MUFFLER CONSTRUCTION Filed Sept. 18, 195'? 4 Sheets-Sheet 4 MvN w H United States atet 3,035,654 MUFFLER CONSTRUCTION Walter H. Powers, Jackson, Micln, assiguor, by mesne assignments, to Walker Manufacturing Company, Racine, Wis., a corporation of Delaware Filed Sept. 18, 1957, Ser. No. 634,792 3 Claims. (Cl. 181-54) My invention relates to exhaust mufllers of the type that are used to silence internal combustion engines in automobiles.

It is an object of my invention to provide a muffler having excellent silencing characteristics and which may be made at a somewhat lower cost than muffler constructions for doing the same job of silencing that have been heretofore available.

Another object of my invention is to provide a mufiier construction which incorporates a number of silencing features within a very small volume, thus reducing the size of the muflier unit so that it can be more readily placed in modern automobiles where space is at a premium.

lAI10il16l' object of my invention is to provide a dual muflier system in which there are two exhaust lines, one for each of two banks of engine cylinders, each exhaust line having a front muffler and a rear silencing element which is intended particularly to act as a resonator.

Another object of my invention is to provide a dual muflier system in which the front mufflers are physically disposed in a different manner than the rear mufliers.

The invention is illustrated in preferred forms in the accompanying drawings in which:

'FIGURE 1 is a schematic view showing a dual mufiier system;

FIG. 2 is a cross section through the muflier used at the front of the exhaust line in FIG. 1;

FIG. 3 is a cross section taken along the line 33 of FIG. 2;

FIG. 4 is a side elevation taken FIG. 2;

FIG. 5 is a cross section through the rear muffler of the exhaust line in FIG. 1;

FIG. 6 is a section taken along the line 6-6 of FIG. 5;

FIG. 7 is a side elevation taken from the right of FIG. 5;

FIG. 8 is a cross section through a form of muffler that may be substituted for the mufller of FIG. 5, that is it may be used as a rear muflier in the dual exhaust line of FIG. 1;

FIG. 9 is a cross section taken along the line 99 of FIG. 8; and

*FIG. 10 is a side elevation FIG. 8.

In FIG. 1 there is shown a dual exhaust system for silencing the opposite sides of a V-8 engine 1. The exhaust gases are led from the opposite banks of cylinders in the engine 1 through exhaust pipes 3 to front muffiers 5 and 7. The front mufflers 5 and 7 are of identical construction except that they are enantiomorphic, like left and right hands. Gases leaving the front mutflers 5 and 7 flow through connecting exhaust pipes 9 to rear mufllers 11 which are of identical construction. The mufilers 5 and 7 as well as the mothers 1 1' are elliptical or oval in cross section. The mufflers 5 and 7 are dis posed so that the major axis or width of each is horizontal. However, to provide optimum placement the mufflers 11 are each disposed so that the major axis or width of each is vertical. It is contemplated that in the automobile in which this system will be used the mufflers '11 will be disposed within the fender well for the rear wheels of the automobile. Tail pipes 13 conduct gases from the from the right of taken from the right of rear mufflers 11 to the rear of the vehicle and discharge the silenced exhaust gases to atmosphere.

Considering first the muffler construction 5, which is the same as the construction of muifler 7 except for the parts being reversed within the shell, this mufiier has a shell construction which consists of an inner shell 21 which is lock seamed at v23. A layer of asbestos and an outer cover 25 are wrapped around the inner shell 23, the cover 25 being lock seamed at 27. An inlet end header 29 is interlocked with the ends of the shell 21 in a head 31 and an outlet header 33 is interlocked with the other end of the shell 21 by means of a turned over head 35. The headers 29 and 33 have no openings in them, other than for the admission of inlet and outlet pipes, with the single exception of a very small (0.12" diameter) outlet hole 34 which is located on the bottom side of the outlet header 33 as will be seen in FIG. 4. This constitutes a drain hole for condensed liquids from in the muflier but it is so small that it will not have any acoustic effect which is adverse to the silencing properties of the muflier.

The inlet header 29 is bowed outwardly and is provided with an outwardly extending neck 37. An inlet bushing 39 extends through the neck in the header '29 and terminates a short distance inside of the muflier. The inlet bushing is expanded on opposite sides of the flange 37 and the portion in alignment with the flange 37 is expanded into tight engagement with it and spot welded thereto. Seated in the inlet end of the bushing 39 and supported by it is an inlet conduit or tube 41. This is a spot Welded connection which can be performed prior to attachment of the head 29 to the shell by way of the bead 311. After such attachment is performed the bushing 39 is expanded into contact with the neck 37 so that spot welding to the neck can be performed. The inlet tube 41 has three series or groups of louvers 43 formed in its side wall and its outlet end fits in a neck 45 on a partition 47 which has a circumferential flange that is spot welded to the shell 21. The groups of louvers 43 are each surrounded by chambers 49 which are provided by a pancake construction 50 consisting of a shell that is split along the midplane and the flanges at the midplane are attached together as seen in PEG. 3. The sections between the chambers 49 are reduced in diameter so that they engage and are supported upon the pipe 41 as clearly seen in FIG. 2.

Gas entering through the inlet bushing 39 passes along the pipe 41 and empties into a chamber 51 that is formed in the shell by the partition 47 and a partition 53 which is spaced from it. The partition 53 also has an outwardly directed circumferential flange which is spot welded to the shell 21. The volume 51 constitutes a cross over passage since the partition 53 is imperforate and gas entering the volume 51 from the inlet tube 41 passes transversely across the muffler and enters a necked opening 55 formed in the partition 47. Fitting around the neck opening 55 is a cup 57 which has a radial flange 59 running around its circumference and which flange is spot welded to the face of the partition 47. The space within the cup 57 also encloses a necked opening 61 also having a forwardly directed flange and which serves as a seat for an outlet tube 63. Gas will therefore pass from chamber 51 into the cup 57 and reverse direction and flow toward the rear of the muflier through the outlet tube 63. The cup 57 also has a flanged neck 65 formed therein around which is spot welded a tuning tube 67. The center line of the tube 67 is oifset slightly from the center line of the tube 63 but the two tubes are oppositely facing across the volume of the cup 57; however, the cup could be reversed so that the tube 67 is substantially aligned with opening 55 if such arrangement is desirable. The tuning tube 67 pases through a chamber 69 which ,bers or long tuning tubes.

exists in the shell between the partition 47 and a partition 71. It is supported upon a flanged neck 73 in the partition 71 and extends into the chamber 75 between the partition 71 and .the inlet header 29, terminating near the header .29 as seen in FIG. 2. The partition 71 has a necked opening 77 which extends toward the rear of the muffler formed in it so that gas and sound waves in the chamber 75 can also communicate'through the neck 77 withthe chamber 69. The partition 71 has a forwardly extending flange 79 around the bottom thereof which as seen in FIG. 3 fits on the top of the pancake assembly 50. The partition 71 is also provided. with smaller flanged openings 81 which connect the chambers 75 and 69. These two chambers thus act as one very large chamber occupying more than half the volume of the muffler and working in conjunction with the tuning tube 67 which is about one half the total length of the mufller to silence low frequencies.

The space between the partition 53' and the outlet header 33 constitutes an additional sound silencing chamber 82 and gas passing through the pipe 63 is in communication with it through the louvers 83, chamber 82 thus constituting a large spit chamber. The rear end of the tube 63 is seated in a drawn neck 85 on the outlet header 33, the neck 85 constituting the outlet bushing for the muffler.

In operation, gas entering the muffler 5 through the inlet bushing 39 will pass along the length of the inlet tube 41 and enter the cross over chamber 51. While passing through the pipe 41 it issilenced in the three small spit chambers 49 which will serve to attenuate high frequencies andrough noise. Gas in the cross over chamber 51 immediately enters another cross over chamber provided by the cup 57 and reverses direction to enter the outlet pipe 63 through which it flows to the outlet bushing 85. In passing along the outlet pipe 63.addi-. tional sound attenuation occurs because of the action of the spit chamber 82. communicating with. the pipe through the louvers 83. Low frequency or heavy notes are silenced through the tuning tube 67 which is of substantial'length and which empties into the chamber 75. This chamber has its action compounded with the chamber 69 by means of the openings 77 and 81. Gas entering these chambers must, of course, flow back through them through the tuning tube 67 and findits way out through the outlet pipe 63. v

Each of the partitions 47, 53, and 71 is provided on its top and bottom edges very close to the surfaceof the shell 21 with openings 87, these openings being located on the minor diameters of the shellat the midplane or widest;width thereof. They constitute an internal drain: age feature. The holes are preferably A diameter as it has been found that if they are substantially smaller they will clog up and if they are much larger they will have an adverse effect on the functioning of the mufiierto silence the gases. Therefore, the.%" size may be considered to be reasonably critical. As the automobile; and thus the mufflers 5 and 7, rocks back and forth water can flow from one end of the mufller to the otherthrough the openings 87. Thus, it can go from the cool portions of the muffler to the hot portions and be vaporized and flow out of the muffler in the exhaust gases. This is particularly important in dual muffler systems since they run somewhat cooler than the single systems. Also to assist in drainage, if necessary, the small opening 34 previously mentioned is formed in the outlet header 33 on the bottom side thereof as seen best in FIG. 4.

Gas leaving the mufflers 5 and 7 may still be incompletely silenced, particularly in the large high horse power engines of the present day. In modern automobiles the sound problem is complicated by the use of automatic transmissions resulting in the introduction of low power notes the removal of which requires very large cham- The mufflers 11 are located behind the muiflers 5 and'7 and located asclose as possible -to the anti-node of the most prominent standing wave in the system and because of this location its volume is less than if it were placed in front of the muffler 5 or 7.

As seen in FIGS. 5-7, the muffler 11 comprises an inner shell 101 which is lock scanned at 103 and around which is wrapped a layer of asbestos and then an outer cover 1117 which is lock seamed at 109. The ends of the shell 1111 are closed by an outwardly bulged inlet header 111 and an outwardly dished outlet'header7113 which are each interlocked with the ends of the inner casing 191.

The space within the shell 101 is divided into chambers 115, 117, and 119 (which preferably occupies more than half the volume of the shell) by the twopartitions 121- and 123 each of which has circumferential flanges extending toward the forward or inlet end head that are spot welded to the shell 101. An inlet bushing 125 is expanded and spot welded to a neck 127 on the inlet header 111 and it also is seated within a neck 129 of the partition 121 andspot welded toit, the inside-end of the bushing 125 being flared outwardlyas shown at 131 to catch behind the partition 121. In alignment with the opening provided by the inlet bushing 125 butspaced from it across the width of the chamber 117 is an imperforate tuning tube 133, the outlet endof this tube emptying into the resonator chamber 119 close to the outlet header 113. It will be seen that gas flowing through the tube 133 must return through'it' back'to the cham ber 117. The outlet tube 135 is supported at its inlet end by spot welds which attach it to a forwardly extending flange 137 on the partition 123. The, outlet end of the outlet pipe 135 is spot weldedgto an enlarged diameter portion 139 on the drawn outlet neck 141 formed in the outlet header 113. The outlet tube 135 has three groups of louvers 143 formed in the ;wall thereof and extending circumferentially around it similar to the louvers 43. These louvers empty into a series of spit chambers 145 which are separated from each other and which surround each of the groups of louvers 143: The spit chambers 145 are provided by a pancake construction 147 which consists of a pair of opposite stamped dished sheet metal sections which have mating flanges 149 that are spot welded together and which extend radially with respect to the axis of the pipe. The ends of the sections are reduced so as to fit the pipe 135 as seen at 151 and 153 and intermediate portions are also reduced so that they fit the pipe and are spot welded to'it as seenat 155. A hanger strap 157' is spot welded at 159 to theflange 1490f the pancake construction 147 and its other end is spot welded at 161 to the outlet end of the tuning tube 133 so as to furnish support for it and eliminate the need for apartition to furnish such support. i l I l w The partition 121 has a pair of necked openings 163 and 165 which communicate the chamber 117 with the chamber 115. The partition 121 will.serve,to eliminate head ring at the inlet end of themuffler and the. small volume provided there, largely because of the outwardly dished shape of'the inlet header 111, will serve to attenuate certain frequencies.

The gas will enter the muffler 11 through the inlet bushing from the pipe 9 and flow through it into the chamber 117. This gas can flow transversely of the length of the muffler across the space 117 and enter the inlet end of the outlet pipe andflow through it di rectly through the mufller 11 into the tail pipe 13. However, heavy notes and heavy slugs of gas will pass through the tuning tube 133 and enter the dead end chamber 119 and be attenuated there. Additional silencing is obtained in the spit chambers and in the chamber 115. V

The partitions 121 and 123 have the internal drainage openings 1'71 formed adjacent tothe shell 101 at the top andthe bottom of the muffler, it being notedthat this muffleris disposed so that the major axis is vertical. The openings 171'like the openings 87 should be approxi-' mately A" in diameter. Theoutlet. header 113. also may have a 0.12" diameter opening on its bottom side as shown at 173, it being noted that FIG. 7 shows the mulfler turned upside down from the position that it would be used in the system shown in FIG. 1.

FIGS. 8-10 show a modified muflier construction 200 which may be used in the system of FIG. 1 behind muffiers 5 and 7 and located at the anti-node of the most prominent standing wave in each of the two exhaust lines. The muffler 200 has an inner shell 201 which is lock seamed at 203. It is surrounded by a layer of asbestos 205 which in turn is held in place by a cover 207 that is lock seamed at 209. The inlet header 211 is bulged outwardly and interlocked in a reverse bend joint at 213 while the outlet header 215 is also interlocked with the shell 201 in reversely bent bead 217.

The inlet header 21 1 has an outwardly extending flanged neck 214. Seated in the neck 214 is an inlet bushing 216 which is expanded at opposite sides of the neck 214 and and into tight engagement with the neck so that it can be spot welded to the neck. The end of the bushing 216 extends through a rearwardly facing neck 219 formed in a transverse partition 221. that has a circumferential flange that is spot welded to the shell 2'01. Within the outlet end of the bushing 216 is mounted a tuning tube 225 and it along with the bushing 2116 are spot welded to the neck 219 as seen at 227. The partition 221 forms a chamber 229 between it and the inlet header 2 11 which is preferably less than half the volume of shell 20-1. Gas entering the mufiier through the inlet bushing 2116 can enter the chamber 229 without resistance because of a very large and non-restrictive opening 261 which is cut in the side of the bushing 216. The tube 225 is imperforate and extends along the length of the muflier and terminates in an open end near the outlet header 215'. Thus, gaseswhich enter it will be dumped into a chamber 233 which is formed between the outlet header 215 and a transverse partition 235 which is provided with a circumferential flange whereby it may be spot welded to the inside of the shell 201. The space between the partition 235 and the partition 221 constitutes a chamber 237 which communicates with the chamber 233 through a flanged neck 239 so that the two resonators act together and constitute a compound resonator chamber for attenuating heavy notes entering the mufiler 200 and passing along the tuning tube 225.

Outlet pipe 241 is supported in a flanged neck 243 on the partition 221 and its outlet end is supported and spot welded to a drawn neck or nipple 245 formed integrally with the outlet header 215. The outlet pipe 241 is provided with three sets of louvers 247 and these are surrounded by a pancake assembly formed of complemental halves which have radial flanges 251 which are spot welded together along a medial plane and which are necked down appropriately to provide sections 253 at opposite ends which are spot welded to the circumference of the tube 241 and intermediate necked down sections 255 which are also spot welded to the circumference of the tube. The assembly 249 provides the spit chambers 257 which act upon sound waves reaching it through the louvers 247 to attenuate high frequencies in a knownmanner. The intermediate partition 235 is provided with a flanged opening 260 through which the pancake assembly 249 extends and upon which it is supported as can be seen in FIGS. 8 and 9.

Gas entering the mufller 200- through the inlet nipple 216 can ilow through the very :large unrestricted opening 231 transversely across chamber 229 into the outlet pipe 241 and down its length out of the muffler into the tail pipe 13. While passing along the pipe 241 high frequency sounds will be attenuated in the three spit chambers 257.

Heavy notes and large slugs of gas will pass from the inlet bushing 216 directly along the aligned tuning tube 225' into the chamber 2 3 and through neck 2-39 into chamber 237 where they will be attenuated. It will be seen that the particular construction of the inlet nipple 216 provides a rigid mufiier eliminating the need for a partition.

The partitions 221 and 235 have the drainage holes 261 formed on the top and bottom thereof adjacent the shell 201. These should be A" in diameter to avoid plugging and to avoid effecting the acoustic characteristics of the mufiier. These holes will permit the water to flow longitudinally from one chamber to another as the mufiler is rocked in usage thus permitting the condensate to come in contact with hot gases, be vaporized, and carried out through the outlet pipe. At the bottom of the outlet header 215 a 0.12 diameter drainage opening 263 is formed, this size being small enough so that it does not adversely aifect the acoustic characteristics of the muffler.

What is claimed is:

1. In a muffler construction a shell having inlet and outlet headers, an inlet conduit in said shell extending through said inlet header, transverse partitions within said shell, said inlet conduit having an end thereof suppoited in one of said partitions, a second of said partitions being spaced from the end of said inlet end pipe, an opening in said partition which supports the end of said inlet pipe, at second opening in said supporting partition, an outlet pipe supported in one of said openings and extending through said second partition and through the outlet header and parallel to said inlet conduit, and a cross over member attached to said supporting partition and direct ing gas flow from the space between the two partitions and reversing it so that it will flow from said space into said outlet pipe.

2. The invention set forth in claim 1 including a tuning tube attached to said cross over member and opening into the space in said shell between said inlet header and said supporting partition.

3. In a muliler construction, an elongated shell having an inlet end and an outlet end, transverse partitions in said shell dividing it into longitudinally separated chambers, an inlet tube extending through said inlet end into said shell and terminating in an outlet therein, an outlet tube extending through said outlet end into said shell and terminating in an inlet therein, means in the shell directing gas flow from the outlet of the inlet tube to the inlet of the outlet tube, one of said tubes extending over more than half of the length of the shell and the space Within the shell surrounding said one tube comprising a resonator chamber, a tuning tube connected to said means and extending into said resonator chamber and having a length at least approximately half that of the shell, and means surrounding the one tube and located in said resonator chamber and forming high frequency noise attenuating means acting on gas flowing through said one tube.

References Cited in the file of this patent UNITED STATES PATENTS 

